Rotary steam engine



July 1, 1969 H. A. PRATT 3,452,643

4 l ROTARY STEAM ENGINE Filed Aug. 22, 196e United States Patent O 1 Claim ABSTRACT OF THE DISCLOSURE This invention concerns a rotary steam engine in which a trilobe rotor operates in a trochoid chamber and through eccentrically arranged means drives a power take-off shaft.

This invention relates to steam engines particularly of the rotary type, and in particular a rotary steam engine having a triangular-shaped rotor traveling in an eccentrically disposed path wherein an eccentric rotates within the rotor, and wherein the rotor is provided with positive seals on all sides and across the apexes.

The object of this invention is to provide a rotary steam engine of compact design and in which the construction of the engine is both simplified and economical.

Another object of this invention is to provide a rotary steam engine with a minimum of moving parts and which is of simple and economical construction.

Other features and advantages of this invention will appear from the following description, taken in connection with the drawing, wherein:

FIGURE l is a cross section through the engine showing the rotor with one of the points or lobes on the bottom center of the engine.

FIGURE 2 is a similar view showing the rotor turned through an angle of 30 degrees.

FIGURE 3 is a view similar to that shown in FIGURE 1 showing the rotor with one of the points turned through an angle of 60 degrees.

FIGURE 4 is a view also similar to that shown in FIGURE l, and wherein the rotor has traveled through an angle of 90 degrees.

FIGURE 5 is a perspective View showing the parts eX- ploded and wherein parts are omitted and other parts broken away.

FIGURE 6 is a longitudinal section taken on line 6-6 of FIGURE 3.

The sections showing the parts are indicated by the numerals 1, 2, 3 and 4, as indicated by corresponding numerals in FIGURE 6.

While one embodiment of the invention is illustrated in the above-referred-to drawing, it is to be understood that the drawing is merely for the purpose of illustration and that various changes in construction may be resorted to in the course of manufacture in order that the invention may be utilized to the best advantage according to circumstances which may arise Without in any manner departing from the spirit and intention of the device, which is to be limited only in accordance With the appended claims. And while there is stated the primary field of utility of the invention it remains obvious that it may -be employed in any other capacity wherein it may be found applicable.

In the accompanying drawings, and in the following specification the same reference characters are used to designate the same parts and elements throughout and in which numeral 10 refers to the housing of the engine, including an outer Wall 11 with cooling chambers or water jackets 12, a shaft 13 on which the parts are mounted, a rotor 14 through which the shaft 13 extends, and a flywheel 18 which is positioned on the shaft 13'.

The engine housing 10 is provided with a flange 19` at ice one end through which an intake port 20 extends, and the flange is also provided with an exhaust port 21. A flange 22 at the opposite end of the housing is provided with an exhaust port 23 and an intake port 24.

The shaft 13 is rotatably mounted in partitions 25 and 26 through bearings 27 and 28 and, as shown in FIGURE 6, the shaft is provided with a counterweight 29. As shown in FIGURE 6, partitions 25 and 26 form, with the adjacent walls of housing 10, three chambers in the lift one of which counterweight 29 is located, inthe middle one of which rotor 14 operates and in the right one of which flywheel 18 is mounted.

A ring gear 15 is mounted internally of, or integral with, the rotor 14, with an eccentric 16 secured to shaft 13 and on which the rotor 14 is positioned, and a reaction gear 17 secured to partition 25 and on meshing with the ring gear 15.

The rotor 14 is provided with seals 30 at the apeXes and seals 31 and 32 at the sides.

It will be understood that seals of other types and designs may be used and such seals are installed on the apex and sides of the triangular-shaped rotor to insure tight seals as the rotor turns in 4the trochoid chamber.

The rotary steam engine of this invention is provided with one steam intake port, and one exhaust or outlet port on each side of the housing; and as the rotor turns 30 degrees the eccentric on the main shaft turns degrees, whereby the rotor makes one turn for each three revolutions of the main shaft.

The triangular-shaped rotor turns in a trochoid chamber by means of an eccentric on the main shaft and a reaction gear mounted concentrically with the main shaft. The reaction gear is mounted on the end cover, and the power impulses are transmitted from the rotor to the eccentric and main shaft.

The rotor is provided with a ring gear on one side to mesh with the reaction gear on the end cover. The opposite side of the rotor has a bearing surface and this is mounted on the eccentric on the main shaft.

The reaction gear on the end cover and the ring gear on the rotor have a ratio of 2 to 3, and when the rotor turns 30 degrees the eccentric on the main shaft turns 90 degrees, so that the rotor turns one time for each three revolutions of the main shaft.

The trochoid chamber or housing has one intake port and one exhaust port on each side of the housing, that is, two intake and two exhaust ports per rotor. Due to the construction it will -be seen that the rotor is under steam pressure at all times since there always are two overlapping power strokes on opposite sides of the rotor. See for example concurrent steam admissions through inlet ports 20 and 24. Also the housing has passages for coolant flow or for Ia steam reheat regenerative cycle.

From the foregoing description, it is though to be obvious that a rotary steam engine constructed in accordance with this invention is particularly well 4adapted for use, by reason of the convenience and facility with which it may be assembled and operated, and it will also be obvious that the invention is susceptible of some change and modification without departing from the principles and spirit thereof, and for this reason it is not desired to be limited to the precise arrangement and formation of the several parts herein shown in carrying out the invention in practice, except as claimed.

What is claimed is:

1. A rotary steam engine comprising a housing having inner and outer rwalls with cooling chambers therebetween, said housing including -a pair of flanges formed diametrically opposite to one another on said housing, a pair of diametrically opposed inlet and outlet openings formed in said flanges for admitting and expelling steam pressure to and from within said housing, a triangularly shaped rotor rotatable in said housing, sealing means at the apices and on opposite sides of the faces of said rotor, spaced-apart partitions formed within said housing to provide separate adjacent chambers therein, a drive shaft eX- tending through said housing and chambers formed therein, bearing members for said shaft carried by said housing and partitions, an eccentric element keyed on said shaft for rotation therewith, said eccentric element disposed entirely within an area formed in said rotor, a ring gear formed in said rotor, a reaction gear mounted on one of said partitions, said reaction gear meshing with the said ring gear, a flywheel keyed to said drive shaft, a counterweight keyed to said shaft, said flywheel disposed completely within one of said chambers, said counterweight disposed completely within a second chamber, said rotor, eccentric, ring gear and reaction gear mounted in a third chamber formed intermediate the aforementioned rst and second chambers, said diametrically opposed inlet and outlet openings extending within the said third chamber for the admission and expulsion of steam to and from within said third chamber, said inlet openings in said anges being so arranged as to maintain said rotor under constant rotational pressure when steam is directed to the said rotor through said inlet means.

References Cited UNITED STATES PATENTS 658,556 9/1900 Pitt 91-56 3,077,867 2/ 1963 Froede 123-8 3,240,189 3/ 1966 Stumpfig 12S-8 3,096,746 7/ 1963 Sollinger. 3,134,370 5/ 1964 Schlr.

FOREIGN PATENTS 410,188 3/ 1945 Italy. 583,035 12/ 1946 Great Britain.

OTHER REFERENCES The Autocar, vol. 111, No. 333 1., Dec. 18, 1959. p. 815.

EVERETTE A. POWELL, JR., Primary Examiner. 

